Thanks for reading and taking the time to respond, Emily. I totally agree that researching, testing, co-designing, and utilizing other ways to involve real end users throughout the design process is a critical part of this. However, there is frequently a point where the design team disengages with the people involved in those activities. If there isn't representation on the team the findings, feedback and insights from co-creation are still processed through the lens of the team members, so as you pointed out, it has to be coupled with team diversity.
And I agree that the ultimate outcome of empathy is not a full picture, but I think the key is that the further removed you are from another person's experience the more fragmented your picture is. Representation on a team decreases the fragmentation.